Investigation of shear stress between roll interfaces in a high-accuracy roll-type stamping transfer system

We investigated the influence of the shear force on a roll-type transfer technique developed to realize high transfer ratio and high positioning accuracy. Roll-type stamping transfer is a promising method for integrating solid-state devices on flexible substrates. However, the accuracy of the roll-type stamping transfer method is insufficient for tiny devices, such as Micro-Electro-Mechanical-Systems (MEMS) sensors, integrated circuits, and surface-mounting chips, because of the shear stress that occurs at the contact of the two rolls. In this work, the shear force was measured at various roll radii and rotational speeds. The results suggest that adjustments of the roll radius can reduce the shear stress to less than 10 kPa. The low shear stress improves the misalignment angle by 2 degrees, with a high roll rotational speed, which enables the development of a hybrid sensing system for flexible and rigid devices at a large-scale.